Liverpool to ban pitch invader who nearly injured Andy Robertson
As the players celebrated the final goal of Sunday's 7-0 drubbing of their rivals, the fan ran onto the pitch and slipped, colliding with Robertson who went down clutching his ankle, although the Scot finished the match.
Merseyside Police said a 16-year-old boy has been arrested on suspicion of encroaching onto a football pitch.
"There is no excuse for this unacceptable and dangerous behaviour. The safety and security of players, colleagues and supporters is paramount," the club said in a statement on Monday.
"The club will now follow its formal sanctions process and has suspended the alleged offender's account until the process is complete.
"If found guilty of the offence of entering the pitch without permission, the offender could face a criminal record and a lifetime ban from Anfield and all Premier League stadiums. These acts are dangerous, illegal and have severe consequences."
The police said their officers were working with the club in relation to the incident.
"He is scheduled to voluntarily attend a police station in Merseyside regarding this incident," it said in a statement.
The fan was led away by stewards and also got an earful from Liverpool boss Jurgen Klopp, who was furious on the touchline as the linesman attempted to calm the German manager.
The result boosted Liverpool's top-four hopes as the Anfield club moved up to fifth, three points behind fourth-placed Tottenham Hotspur with a game in hand. They next play away at relegation-threatened Bournemouth on Saturday.